SAM3SD8C Atmel Corporation, SAM3SD8C Datasheet - Page 368

• Manufacturer Part Number: SAM3SD8C
• Manufacturer: Atmel Corporation

22.8.2
Name:
Address:
Access:
• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst
When the SLOT_CYCLE limit is reach for a burst it may be broken by another master trying to access this slave.
This limit has been placed to avoid locking very slow slaves when very long bursts are used.
This limit should not be very small though. An unreasonable small value will break every burst and the Bus Matrix will
spend its time to arbitrate without performing any data transfer. 16 cycles is a reasonable value for SLOT_CYCLE.
• DEFMSTR_TYPE: Default Master Type
0: No Default Master
At the end of current slave access, if no other master request is pending, the slave is disconnected from all masters.
This results in having a one cycle latency for the first access of a burst transfer or for a single access.
1: Last Default Master
At the end of current slave access, if no other master request is pending, the slave stays connected to the last master hav-
ing accessed it.
This results in not having the one cycle latency when the last master re-tries access on the slave again.
2: Fixed Default Master
At the end of the current slave access, if no other master request is pending, the slave connects to the fixed master the
number that has been written in the FIXED_DEFMSTR field.
This results in not having the one cycle latency when the fixed master re-tries access on the slave again.
• FIXED_DEFMSTR: Fixed Default Master
This is the number of the Default Master for this slave. Only used if DEFMSTR_TYPE is 2. Specifying the number of a mas-
ter which is not connected to the selected slave is equivalent to setting DEFMSTR_TYPE to 0.
• ARBT: Arbitration Type
0: Round-Robin Arbitration
1: Fixed Priority Arbitration
2: Reserved
3: Reserved
368
368
31
23
15
–
–
–
7
SAM3S8/SD8
SAM3S8/SD8
Bus Matrix Slave Configuration Registers
MATRIX_SCFG0..MATRIX_SCFG4
0x400E0240
Read-write
30
22
14
–
–
–
6
29
21
13
–
–
–
5
28
20
12
–
–
4
SLOT_CYCLE
FIXED_DEFMSTR
27
19
11
–
–
3
26
18
10
–
–
2
25
17
9
–
1
DEFMSTR_TYPE
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
ARBT
24
16
8
–
0